This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project has as its goal the evaluation of the effects of a DPP-4 inhibitor on pancreatic islet viability and function, specifically with respect to basal and GLP-1-enhanced glucose-stimulated insulin secretion. The proposal is based upon the observation that DPP-4 inhibition increases islet function in vivo and that pancreatic alpha cells express DPP-4, supporting the hypothesis that DPP-4 inhibitors may have islet-autonomous effects that will be discernable in isolated islets ex vivo. To date, we have established an optimized protocol for macaque islet purification and procedures for static glucose-stimulated insulin secretion.